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Topic: Tint (Read 276 times) |
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inadaze
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Tint
« on: Oct 18th, 2004, 1:34am » |
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i was wondering how turn a color image into a black and white image.
I noticed the tint function but I don't understand how the values in tint(value1,value2,value3) can be used for both saturation-hue-brightness and red-green-blue? is there an indicator that says whether you are using RGB or the other fields?
Thanks
Jay
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Markavian
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Re: Tint
« Reply #1 on: Oct 18th, 2004, 3:08am » |
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Are you trying to create a pure black and white image, or a greyscale image?
There are probably lots of algorithms out there for converting images, you'd probably have more fun trying to write your own.
I imagine using the colour c = get(x, y) would be the best way to go ahead, taking the red(c), green(c) and blue(c) values of the colour and then averging them out to give a grey value, which you then use to recreate the image.
If you want to do pure black and white you'd need to look into dithering functions to represent block shaded areas of the image.
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Markavian
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Greyscale
« Reply #2 on: Oct 18th, 2004, 4:03am » |
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I tried a few things with an imported image I drew, my code is below.
Or you can see it working on my website... http://mkv25.net/index.php?item_id=86
Code:// Load an image and convert to grey scale
size(300, 300);
colorMode(RGB, 255, 255, 255);
BImage cImg = loadImage("house.gif");
image(cImg, 0, 0);
for(int ix=0; ix<100; ix++) {
for(int iy=0; iy<100; iy++) {
// Get colour for ix, iy pixel
color ct = get(ix, iy);
// Calculate averaged grey value
int gval = int(red(ct) + green(ct) + blue(ct))/3;
// Image as averaged grey of three colours / 3
set(ix+100, iy, color(gval, gval, gval));
// Inverted grey image
set(ix+200, iy, color(255-gval, 255-gval, 255-gval));
// Grey image expressed as value of red
set(ix, iy+100, color(red(ct), red(ct), red(ct)));
// Grey image expressed as value of green
set(ix+100, iy+100, color(green(ct), green(ct), green(ct)));
// Grey image expressed as value of blue
set(ix+200, iy+100, color(blue(ct), blue(ct), blue(ct)));
// Red values only image
set(ix, iy+200, color(red(ct), 0, 0));
// Green values only image
set(ix+100, iy+200, color(0, green(ct), 0));
// Blue values only image
set(ix+200, iy+200, color(0, 0, blue(ct)));
}
} |
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